It turns out that recording what's going on is actually quite easy.
First, you need an infrared video camera. They're easily available for several thousand dollars. Or 40 bucks, whichever you like. 8-)
If you have a spare logitech webcam, you can convert it to IR by removing the IR filter. I never knew it had one, but it does. This does make the camera more or less useless for other purposes, but considering that the camera cost me less than a co-pay at the doc, and I had an extra, it was a worthwhile sacrifice.
I can't take credit for the conversion directions. They're here:
Once that's done, go to the logitech website and download their driver pack for your camera. You probably don't need the drivers (windows usually has them anyway), but it comes with a very simple video recorder that easily handles large files.
Hang a wall clock within the camera's field of vision, so you can tell what time each event happens.
Light: You can either use an infrared illuminator, which can be had for $40 or so on the internet, or an lamp or ceiling light with a 100W or bigger incandescent (not fluorescent or LED) bulb, on a dimmer, turned down to a soft glow. Incandescent bulbs throw off a ton of IR light.
Point the camera at the bed, fire up the logitech recording software, make sure the clock is in the frame, and go to bed! A full night runs about 2GB of video.
The next day, you can look at your data in SleepyHead or the software of your choice, and compare what's going on in the charts, with what's going on in your room. For example, I found that at about 5am, my cat stops in for a visit and that a place on my graph where a bunch of apneas showed up was when I rolled over and mashed my mask out of position, then fixed it and never remembered doing anything.
It's really pretty fascinating and well worth sacrificing an old webcam.